DoubleAbsoluteFunction.java

/*
 * $Id: AbsoluteFunction.java,v 1.9 2008/06/26 10:10:34 koga Exp $
 *
 * Copyright (C) 2004 Koga Laboratory. All rights reserved.
 *
 */

package org.mklab.tool.control.system.math;

import java.util.ArrayList;
import java.util.List;

import org.mklab.nfc.matrix.DoubleMatrix;
import org.mklab.nfc.ode.DoublePiecewiseContinuousAlgebraicSystem;
import org.mklab.nfc.ode.PiecewiseUtil;
import org.mklab.tool.control.system.continuous.DoubleBaseContinuousStaticSystem;


/**
 * 入力の絶対値を出力するシステムを表わすクラスです。
 * 
 * @author Koga Laboratory
 * @version $Revision: 1.9 $, 2004/11/12
 */
public class DoubleAbsoluteFunction extends DoubleBaseContinuousStaticSystem implements DoublePiecewiseContinuousAlgebraicSystem {

  /**
   * 新しく生成された<code>AbsoluteFunction</code>オブジェクトを初期化します。
   */
  public DoubleAbsoluteFunction() {
    super(-1, -1);
    setAutoSize(true);
    setHasDirectFeedthrough(true);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public DoubleMatrix outputEquation( final double t, final DoubleMatrix u) {
    return u.absElementWise();
  }

  /**
   * {@inheritDoc}
   */
  @SuppressWarnings("boxing")
  public List<Integer> getPiece( final double t, final DoubleMatrix u) {
    final int size = u.getRowSize();
    final List<Integer> pieces = new ArrayList<>(size);

    for (int i = 1; i <= size; i++) {
      if (u.getDoubleElement(i) < 0) {
        pieces.add(0);
      } else {
        pieces.add(1);
      }
    }

    return pieces;
  }

  /**
   * {@inheritDoc}
   */
  public double getDiscontinuousPoint(final double t1, final DoubleMatrix u1, final double t2, final DoubleMatrix u2) {
    final List<Integer> pieces1 = getPiece(t1, u1);
    final List<Integer> pieces2 = getPiece(t2, u2);

    if (pieces1.equals(pieces2)) {
      return Double.NaN;
    }

    final int number = PiecewiseUtil.getDistinctPiece(pieces1, pieces2);

    final double uu1 = u1.getDoubleElement(number);
    final double uu2 = u2.getDoubleElement(number);

    return t1 + (0 - uu1) / (uu2 - uu1) * (t2 - t1);
  }

  /**
   * @see org.mklab.tool.control.system.SystemOperator#setInputSize(int)
   */
  @Override
  public void setInputSize(final int size) {
    super.setInputSize(size);
    super.setOutputSize(size);
  }

  /**
   * @see org.mklab.tool.control.system.SystemOperator#setOutputSize(int)
   */
  @Override
  public void setOutputSize(final int size) {
    super.setInputSize(size);
    super.setOutputSize(size);
  }
}